Advanced Fuels from Advanced PlantsAbstract:
Today, carbon-rich fossil fuels, primarily oil, coal and natural gas, provide 85% of the energy consumed in the United States. As world demand increases, oil reserves may become rapidly depleted. Fossil fuel use increases CO2 emissions and raises the risk of global warming. The high-energy content of liquid hydrocarbon fuels makes them the preferred energy source for all modes of transportation. In the US alone, transportation consumes around 13.8 million barrels of oil per day and generates over 0.5 gigatons of carbon per year. This release of greenhouse gases has spurred research into alternative, non-fossil energy sources. Among the options (nuclear, concentrated solar thermal, geothermal, hydroelectric, wind, solar and biomass), only biomass has the potential to provide a high-energy-content transportation fuel. Biomass is a renewable resource that can be converted into carbon-neutral transportation fuels.
Currently, biofuels such as ethanol are produced largely from grains, but there is a large, untapped resource (estimated at more than a billion tons per year) of plant biomass that could be utilized as a renewable, domestic source of liquid fuels. Well-established processes convert the starch content of the grain into sugars that can be fermented to ethanol. The energy efficiency of starch-based biofuels is however not optimal, while plant cell walls (lignocellulose) represents a huge untapped source of energy. Plant-derived biomass contains cellulose, which is more difficult to convert to sugars, hemicellulose, which contains a diversity of carbohydrates that have to be efficiently degraded by microorganisms to fuels, and lignin, which is recalcitrant to degradation and prevents cost-effective fermentation. The development of cost-effective and energy-efficient processes to transform lignocellulosic biomass into fuels is hampered by significant roadblocks, including the lack of specifically developed energy crops, the difficulty in separating biomass components, low activity of enzymes used to deconstruct biomass, and the inhibitory effect of fuels and processing byproducts on organisms responsible for producing fuels from biomass monomers.
We are using the latest advances in synthetic biology to engineer plants, enzymes, and microorganisms to more efficiently produce fuels from plant biomass and thereby lower the cost and improve their sustainability. Specifically, we have engineered plants to alter their biomass composition, including lignin length and content, cellulose and hemicellulose content, and functionalization of hemicellulose. In the area of biomass deconstruction, we have developed methods to cleanly and efficiently extract sugars from the plant material. Finally, we have engineer the metabolism of platform hosts (Escherichia coli and Saccharomyces cerevisiae) for production of advanced biofuels, hydrocarbons that can directly replace gasoline, diesel, and jet fuel. Large-scale production of these fuels will reduce our dependence on petroleum and reduce the amount of carbon dioxide released into the atmosphere, while allowing us to take advantage of our current transportation infrastructure.About Jay Keasling
Jay D. Keasling is the Hubbard Howe Jr. Distinguished Professor of Biochemical Engineering at the University of California, Berkeley. He is also the Founding Head of the Synthetic Biology Department in the Physical Biosciences Division at Lawrence Berkeley National Laboratory, and CEO of the Joint BioEnergy Institute. He is considered one of the foremost authorities in synthetic biology, especially in the field of metabolic engineering. His research focuses on engineering microorganisms for environmentally friendly synthesis of small molecules or degradation of environmental contaminants. For example, Keasling’s laboratory has engineered bacteria and yeast to produce polymers, a precursor to the antimalarial drug artemisinin, advanced biofuels, and soil microorganisms to accumulate uranium and degrade nerve agents. He is the recipient of numerous awards, including the 2006 Scientist of the Year Award from Discover Magazine, and a $42.5 million grant from the Bill and Melinda Gates Foundation to develop and distribute the low-cost malaria treatment created in his lab. Dr. Keasling is a Fellow of the American Academy of Microbiology. He received his Bachelor's Degree at the University of Nebraska-Lincoln, and his Ph.D from the University of Michigan.